You're looking at the Honda CVCC engine. It was made to comply with tight 1970s emissions restrictions without the need for catalytic converters. It wasn't exactly what you would call simple.

Things got even more complicated in the '80s as emissions regulations got tighter and Honda had to put in a maze of vacuum tubes, wires, and enchanted elven enchantments to keep the thing legal. You can see them right here. Despite its small size, it's surely one of the more complicated engines ever put in production.